In the field of electrical engineering, capacitors are used for the compensation of reactive power, among other things. Such capacitors normally have a terminal block that can be plugged onto the capacitor.
Such a terminal block for plugging onto a capacitor normally comprises a housing having an electrical current bar arranged inside the housing, the housing having an opening for guiding through a capacitor wire and for electrically contacting said capacitor wire to the current bar, and an opening for receiving an electrical conductor and electrically contacting said electrical conductor to the current bar. Furthermore, some terminal blocks have a further housing opening for receiving a discharge resistor and electrically contacting said discharge resistor to the current bar.
The capacitor wire is guided through the corresponding housing opening and connected directly to the current bar. Moreover, the annular gap between the capacitor wire and the lead-through opening is soldered so as to be gas-tight. Both the electrical conductor and the discharge resistor are inserted through the respective opening into the housing and electrically connected to the current bar using screw connection terminals.
Screw connection terminals, however, have the disadvantage that it cannot be seen from outside whether the screw of the screw connection terminal is tight and therefore whether the electrical conductor and the electrical resistor, respectively, are clamped tightly to the current bar. Furthermore, the screw of the screw connection terminal is to be tightened at a defined torque so that a minimum clamping force is achieved in order to tightly clamp the electrical conductor, which has been inserted into the screw connection terminal, and the discharge resistor, respectively, to the current bar and at the same time, however, not too great a torque is applied that could damage the screw connection terminal.
Moreover, the screws of the screw connection terminal can loosen over time as a result of the influence of temperature changes and shocks such that the clamping effect of the screw connection terminal diminishes and the electrical contact between the electrical conductor and the current bar, or the electrical contact between the discharge resistor and the current bar, is interrupted.